On Friday, 2020-07-17 at 15:38:47 +02, Philippe Mathieu-Daudé wrote: > libFuzzer found an undefined behavior (#DIV/0!) in ide_set_sector() > when using a CD-ROM (reproducer available on the BugLink): > > UndefinedBehaviorSanitizer:DEADLYSIGNAL > ==12163==ERROR: UndefinedBehaviorSanitizer: FPE on unknown address > 0x5616279cffdc (pc 0x5616279cffdc bp 0x7ffcdaabae90 sp 0x7ffcdaabae30 T12163) > > Fix by initializing the CD-ROM number of sectors in ide_dev_initfn(). > > Reported-by: Alexander Bulekov <[email protected]> > Fixes: b2df431407 ("ide scsi: Mess with geometry only for hard disk devices") > BugLink: https://bugs.launchpad.net/qemu/+bug/1887309 > Signed-off-by: Philippe Mathieu-Daudé <[email protected]>
The changes LGTM, presume the 'shrug' is OK to leave in ;) Reviewed-by: Darren Kenny <[email protected]> Thanks, Darren. > --- > Since v1: > - Allow zero-sized drive images (not sure why we need them) > but display a friendly message that this is unsupported > > Unrelated but interesting: > http://www.physics.udel.edu/~watson/scen103/cdsoln.html > --- > hw/ide/qdev.c | 9 +++++++++ > 1 file changed, 9 insertions(+) > > diff --git a/hw/ide/qdev.c b/hw/ide/qdev.c > index 27ff1f7f66..005d73bdb9 100644 > --- a/hw/ide/qdev.c > +++ b/hw/ide/qdev.c > @@ -201,6 +201,15 @@ static void ide_dev_initfn(IDEDevice *dev, IDEDriveKind > kind, Error **errp) > errp)) { > return; > } > + } else { > + uint64_t nb_sectors; > + > + blk_get_geometry(dev->conf.blk, &nb_sectors); > + if (!nb_sectors) { > + warn_report("Drive image of size zero is unsupported for > 'ide-cd', " > + "use at your own risk ¯\\_(ツ)_/¯"); > + } > + dev->conf.secs = nb_sectors; > } > if (!blkconf_apply_backend_options(&dev->conf, kind == IDE_CD, > kind != IDE_CD, errp)) { > -- > 2.21.3
